Motion picture apparatus



Aug. 28, 1934. F. J. LOOMIS MOTION PICTURE APPARATUS Filed July 25, 19322 Sheets-Sheet l INVENTOR FRED J. LOOMlS BY g h M ATTORNEY Aug. 28,1934. F. J. LOOMIS 1,971,454

' MOTION PICTURE APPARATUS Filed July 25, 1952 2 Sheets-Sheet 2 INVENTORFRED J. LOONHS ATTOR N EY Patented Aug. 1934 PATENT; oer-Ice 'MOTIONPICTURE APPARATUS FredJ. Loomis, Haddonfield, N. 1.,asaignor to RadioCorporation of America, a corporation of Delaware Application JIILY 25,1932, Serial No. 624,443

lclaim.

This invention relates to motion picture apparatus, and morespecifically to a cooling system which is adapted to be attached tocommercial types of motion picture apparatus and particularly 16 mm.motion picture apparatus for the purpose of adapting them to the use oflamps of very high candle power. There are on the market a number oftypes of 16 mm. motion picture projectors, which are adapted to usesatisfactorily lamps of wattages of the order of 150 to 250 and whichoperate safely and satisfactorily -withlamps of such power. However, inorder to satisfactorily project pictures on larger screen areas,itbecomes necessary to use lamps of inu creased ,wattage such, forexample, as the 400 watt lamps provided with bi-plane" filaments such asare now on the market. The use of lamps of this nature makes necessarythe provision of a cooling system to prevent softening of the walls tocooling the film and film apertures. It is undesirable to manufactureall projectors of a given type in two different models, one toaccommodate a low power lamp and one to accommodate a high power-lamp,and it is equally undesirable to restrict the design to a lamp of highpower on account of the amount of screen consumed thereby and theextreme'brilliancy of small images produced therefrom or to a lamp oflow wattage on account of the insufllciency of screen illumination.

In my invention I have provided what may be either considered a part ofor attachment fora projector whereby lampsof considerably higher aswattage may be used in any given projector than would be used withoutsaid attachment or part,

and at the same time this attachment or part maybe omitted duringmanufacture and a small lamphouse substituted and the projector thenused with lamps of lower wattage.

One object of the invention isto provide a projector which is readilyinterchangeable to adapt it foruse of lamps of higher lowwattage.Another object of the invention is to provide an inexpensive anddependable means for cooling the lamphouse-and film aperture when lampsof high wattage are used.

Another object of the invention is to provide such a cooling means whichmay be fitted to pro- 50. jectors of commercial type on the market toadapt them for use on lamps of high wattage and without any materialchanges in the said projector. 1 I

Another object of the invention is to provide such adevice which willcontinue to cool the of the lamp within the lamphouse, and also forlamp, lamphouse and film even though the projector motor be stopped.

Another object of the invention is to provide such a device which,although optionally useable, will present the characteristics of being aportion of the machine rather than merely being an attachment addedthereto.

Another object of the invention is the provision of such a projectorincluding a cooling mechanism which will be compact, light andefllcient.

Another object of the invention is to provide a suiliciently effectivecooling mechanism to permit the film to be run immediately over andunder the lamphouse without danger of ignition thereof or damagethereto.

Another object of the invention is the provision of such an air-cooledlamphouse which is of rigid and substantial construction so as toadequately mechanically protect the lamp.

Another object of the invention is the provii .sion, in conjunction withsuch an air-cooled lamphouse, of means whereby the lamp may be quicklyand conveniently removed therefrom in case it should burn out, or forany other reason for being replaced.

In the drawings:

Fig. 1 is a side view of a talking motion picture projector including myinvention.

7 Fig. 2 is a view from the right-hand end of Fig. 1.

These figures illustrate my invention as applied to the commercial typeof 16 mm. talking motion picture equipment which is generally known asthe RCA Victor type PG-38 equip-' ment and as disclosed in detail inapplication of Russell P. May Serial No. 572,804 filed Novemher 3, 1931.This particular projector includes a base portion 1 which, is adapted tocarry a motion picture projector indicated generally by the referencenumeral 2.

The motion picture projector mechanism is built on andinto an electricmotor of suitable type, the end-bells of the said motor indicated at 3and 4 carrying the entire mechanism thereof. The rear end-bell 3 carriesa pair or sprockets 4' and 5 which feed the film F into and out of theentire apparatus. The fihn passes from the sprocket 4' through the filmgate indicated generally at 8 and which is provided near itsbottom withan intermittent film feeding means, the mechanism of which is encased inthe endbell 4 and the film thence passes downward toward the basemember 1. This base member carries the sound pick-up mechanism. Anexciter lamp is housed within the casing 10 and light therefrom isprojected by the optical system 11 in the form of a fine line upon thefilm as it travels around the drum 12. The soundtrack portion of thefilm overhangs the inner side of this drum, and the light passes throughthe sound-track'and is thereafter reflected. to

the interior of the base member 1 where it strikes a photoelectric cellhoused therewithin. This photoelectric cell and its amplifier areshielded mechanically and electrically by this base member 1. Afterleaving the drum 12 the film passes around the rollers 13 and 14 whichassistthedruml2incausingthefilmtomove at a uniform speed past theoptical system 11, and the film then passes upwardly to the sprocket 5and out to the take-up reel. I

In this machine as manufactured for use with a low wattage lamp, thebody 2 of the motor, and the end-bells thereof 3 and! rest directly ontop of the base member 1 and the projector portion of the mechanism isprovided with screw holes 6 and 7 into which the screws 16 and 1'7 areinserted to hold the projector. member upon the base member 1. I

When the machine is thus assembled for the use of a low wattage lamp, alamphouse is attached at the side of the motor 2 to the rear of theend-bell 4 and with the projection lamp therein in proper alignment withthe projection aper'- ture.

In order to adapt this machine to the use of a high-wattage projectionlamp 20, I provide a difierent lamphouse and an appropriate coolingmechanism; .7

Air for the cooling m ism is supplied by a centrifugal blower 21 whichis driven by a small electric motor 22 mounted at the rear of theprojector and connected in parallel with the lamp-and other motorcircuits so that the motor 22 will be in operation at all times when thelamp is turned on. The motor 22 is carried by the casing of the blower21, and this casing in turn is supported at the fiange 23 to which it issecured by the screws 24.

An air conduit 25 is secured to thebase mem- I her 1 by the screws 16and 17 and additional screws 16' and 17' secure the motor 2 and anattendant mechanism to the top of the member 25. 'It should be notedthat this requires ture 28. The walls continue upwardly from the portion26 and form the body of the lamphouse which, as shown in Fig. 2, passesrather closely around the body of the motor 2 and provides a slight airspace 29 between the wall of the lamphouse and the body of the motor inorder to avoid overheating of the motor from radiation.

The lamphouse is generally referred to by the reference numeral 30 andis provided at its outer sidewith acoverplate3lwhichmayberemoved togiveacoesstotheinteriorofths lamphouseforthepurposeofsdiustingthslamporthsrefisctor 32. The top of the lamphouseconsists of the cover member 33 which is held in proper alignmenttherewith by a dowel pin and stud and is firmly secured thereto by theknurled nut 34 upon the stud 35. This cover 33 provides an airpassageextending to the right in Fig. 2 and terminates in an upwardlyextending esitportion 36 which directs the heated air upward and awayfrom the projector.

The lamp 20 may be removed by removal of the nut 34 when the entirecover member 33-38 has be lifted off, thereby giving access to theinterior of the lamphouse.

The configuration of the cover as is such that asshowninFlg. 1,thefilmmaypamoverthe top thereof without coming in contact with thesurface, and the heatedair is directed laterally to such a distance thatnone of it can impinge upon the film. It is thereby made possible tosafely lfl) use a high wattage lamp in this type of projector wherelamp, reels, and projection aperture are allinalignmentandthefilmiscausedtopassover and under the lamp.

The provision of the motor 22 independent of 10s the motor 2 insuresthat the blower will continue to operate even. though the film feedingmechanism should fail due to either failure of motor 2 or to a fault inthe mechanical portion of the device, and the probability of ignition ofthe film is 11,) thereby decreased. The lamphouse 30 has, of course, anaperture at the front in proper cooperative relation with the projectionaperture 28 and a certain amount of the air forced into the lamphouse 30from the conduit 25 escapes through ,this aperture to the filmgate andthe filmat the projection aperture, both of which'lt assists in cooling.

It will be seen'that I have thus provided a mechanism or apparatus whichis capable of asm sembly for use with either high or low wattage lamps,and I have accomplished this without requiring a large number ofdifierently designed parts for the two purposes, which latter wouldgreatly increase production costs due to increased 12 stocks of partsrequired and decreased numbers of parts produced of any one type.

I claim:

Motion picture apparatus comprising a unit, a projector unit adapted tobe supported 11) upon said base unit and secured thereto, and an aircooling unit, means thereon adapted to be secured upon said baseimit andmeans thereon for securing the projector unit in the same manner as theprojector unit would have been secured to the base unit, whereby theprojector unit may be selectively mounted either directly upon the baseunit or upon the said air cooling unit which in turn may be mounted uponthe base unit.

I FRED J. 1.001118.

